Linear IV PK simulator: bolus, infusion, and repeated dosing; central/peripheral concentration curves, terminal half-life, AUC, Cmax/Cmin, loading dose, and maintenance rate.
This is an IV linear PK teaching model. It omits absorption, saturable metabolism, protein binding, organ-specific physiology, and patient variability.
Live graphs
About this model
This simulator implements a linear intravenous pharmacokinetic compartment model. In the 1-compartment setting, drug enters a central volume V_c, concentration is C=A_c/V_c, and clearance removes drug at rate CL·C. In the 2-compartment setting, a peripheral amount A_p exchanges with the central compartment through intercompartmental clearance Q, creating a distribution phase followed by a slower terminal elimination phase. The dosing input can be a single IV bolus, a zero-order infusion, or repeated doses every τ hours. The plots show central concentration, optional peripheral concentration, target concentration, and input timing. Readouts report terminal half-life, trapezoidal AUC, Cmax and late Cmin, a simple loading-dose estimate, maintenance infusion rate for the selected target, and percent of simulated time above target.
Who it's for: Students in pharmacology, biomedical engineering, physiology, or clinical sciences learning dose-concentration-time relationships and compartment models.
Key terms
Pharmacokinetics
Compartment model
Bolus dose
Infusion
Clearance
Volume of distribution
Half-life
AUC
Loading dose
How it works
Interactive pharmacokinetics compartment model: compare 1- and 2-compartment IV bolus/infusion dosing, concentration-time curves, half-life, AUC, and loading-dose intuition.
Key equations
dA_c/dt = R_in − (CL/V_c)A_c − (Q/V_c)A_c + (Q/V_p)A_p, dA_p/dt = (Q/V_c)A_c − (Q/V_p)A_p, C = A_c/V_c. For one compartment set Q = 0.
Frequently asked questions
Why does the 2-compartment curve often fall in two phases?
After an IV dose, drug first distributes from the central compartment into peripheral tissues, causing a relatively fast drop in central concentration. Later, central and peripheral compartments equilibrate and the terminal slope mainly reflects elimination plus redistribution.
What does loading dose mean here?
The loading-dose readout is target concentration times an apparent volume of distribution. It is a first-order estimate for reaching the target rapidly; real dosing also depends on safety, bioavailability, distribution kinetics, and therapeutic window.
What are the limitations of this model?
It assumes linear IV pharmacokinetics with constant volumes and clearance. It omits absorption, saturable metabolism, protein binding, renal/hepatic physiology, active metabolites, and patient variability.